Her best options are through dual citizenship. Because when she naturalized as a US citizen, she lost her Philippines citizenship until she repatriates.
Dual citizenship allows more flexibility with Philippines residency and property ownership because foreigners can not buy/own real estate. Also, one has more control when transferring from one's own US account to one's own Philippines account as opposed to transferring to a second-party international account. My spouse transfers from her US bank to her Philippines bank all the time.
I believe most US retirement pensions, Social Security, etc. have fewer problems distributing into the US accounts than foreign banks, so the best bet is to continue receiving in the US banks. Plus, transferring on your own terms, you have more leverage with exchange rates, etc., as opposed to direct deposit to a foreign bank, in which they have to follow the exchange rate of the timed deposits. My spouse has been transferring more lately since the 1 USD has been over 58 PHP.
As someone mentioned, she will need to continue to file US taxes, FATCA, FinCen, or whatever future requirements, to avoid problems with the US government. Plus, she may need to fulfill the Philippines tax requirements--whatever that may be in the future.